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netfilter: nat: fix spurious connection timeouts 

Sander Eikelenboom bisected a NAT related regression down
to the l4proto->manip_pkt indirection removal.

I forgot that ICMP(v6) errors (e.g. PKTTOOBIG) can be set as related
to the existing conntrack entry.

Therefore, when passing the skb to nf_nat_ipv4/6_manip_pkt(), that
ended up calling the wrong l4 manip function, as tuple->dst.protonum
is the original flows l4 protocol (TCP, UDP, etc).

Set the dst protocol field to ICMP(v6), we already have a private copy
of the tuple due to the inversion of src/dst.

Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Fixes: faec18dbb0 ("netfilter: nat: remove l4proto->manip_pkt")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2019-02-08 16:39:52 +01:00 committed by Pablo Neira Ayuso
parent c4c07b4d6f
commit 8303b7e8f0
2 changed files with 2 additions and 0 deletions
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1
net/ipv4/netfilter/nf_nat_l3proto_ipv4.c
View File

@ -215,6 +215,7 @@ int nf_nat_icmp_reply_translation(struct sk_buff *skb,
/* Change outer to look like the reply to an incoming packet */
nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
target.dst.protonum = IPPROTO_ICMP;
if (!nf_nat_ipv4_manip_pkt(skb, 0, &target, manip))
return 0;

1
net/ipv6/netfilter/nf_nat_l3proto_ipv6.c
View File

@ -226,6 +226,7 @@ int nf_nat_icmpv6_reply_translation(struct sk_buff *skb,
}
nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
target.dst.protonum = IPPROTO_ICMPV6;
if (!nf_nat_ipv6_manip_pkt(skb, 0, &target, manip))
return 0;